ASTM F392/F392M-23

Standard Practice for Conditioning Flexible Barrier Materials for Flex Durability

SIGNIFICANCE AND USE
5.1 This practice is valuable in determining the resistance of flexible packaging materials to flex-formed pinholes. Conditioning levels A, B, or C are typically used. Reference Practice E171 and Guide F2097.  
5.2 Conditions D and E are typically used for determining the effect of flexing on barrier properties and transmission rates related to gas and/or moisture.  
5.3 This practice does not measure or condition materials for abrasion related to flex failure.  
5.4 Failures in the integrity of one or more of the plies of a multi-ply structure may require alternative testing. Supplementary permeation testing using gas or water vapor can be used in conjunction with the flex conditioning to measure the loss of ply integrity. Other test methods may be used after flexing for assessment of presence of pinholes. For a list of test methods, refer to Guide F2097.
FIG. 1 Planar Evolution of Gelbo Shaft Helical Groove 30.70 mm [1.20 in.] Diameter Shaft  
5.4.1 The various conditions described in this practice are to prevent evaluating a material structure with an outcome of too many holes to effectively count (normally greater than 50), or too few to be significant (normally less than five per sample). Material structure, testing basis, and a mutual agreement with specified objectives are to be considered in the selection of conditioning level for testing.
SCOPE
1.1 This practice covers conditioning of flexible barrier materials for the determination of flex resistance. Subsequent testing can be performed to determine the effects of flexing on material properties. These tests are beyond the scope of this practice.  
1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 30-Sep-2023
• ICS: 55.040 - Packaging materials and accessories
• Technical Committee: F02 - Primary Barrier Packaging
• Drafting Committee: F02.50 - Package Design and Development

Relations

• Replaces: ASTM F392/F392M-21 - Standard Practice for Conditioning Flexible Barrier Materials for Flex Durability
• Effective Date: 01-Oct-2023
• Refers: ASTM F2097-23 - Standard Guide for Design and Evaluation of Primary Flexible Packaging for Medical Products
• Effective Date: 01-Oct-2023
• Refers: ASTM F2097-20 - Standard Guide for Design and Evaluation of Primary Flexible Packaging for Medical Products
• Effective Date: 01-May-2020
• Referred By: ASTM F1052-20 - Standard Test Method for Pressure Testing Vapor Protective Suits
• Effective Date: 01-Oct-2023
• Referred By: ASTM F1296-08(2023) - Standard Guide for Evaluating Chemical Protective Clothing
• Effective Date: 01-Oct-2023
• Referred By: ASTM F3352/F3352M-23b - Standard Specification for Isolation Gowns Intended for Use in Healthcare Facilities
• Effective Date: 01-Oct-2023

Overview

ASTM F392/F392M-23: Standard Practice for Conditioning Flexible Barrier Materials for Flex Durability provides a standardized procedure for conditioning flexible barrier materials, such as those used in flexible packaging, to evaluate their resistance to flex-induced failures like pinholes and degradation of barrier properties. This practice is essential for manufacturers and testers to determine how flexible packaging materials withstand mechanical flexing before and during use, helping to assess their suitability for protecting contents against environmental factors like moisture and gas transmission.

This standard is published and maintained by ASTM International, aligning with global standardization principles set by the WTO Technical Barriers to Trade (TBT) Committee. It provides defined flex conditioning methods but does not encompass post-conditioning evaluations, such as permeation testing, which must be conducted separately.

Key Topics

• Flex Durability Conditioning Levels

  • Five different conditioning levels (A, B, C, D, and E) are defined, varying in severity and cycle count to suit different end-use requirements.
  • Conditions A, B, and C are typically used for resistance to pinhole formation.
  • Conditions D and E are utilized for assessing the impact of flexing on barrier properties like gas and moisture transmission rates.

• Testing Objectives

  • The standard focuses on conditioning, not on abrasion-related flex failures.
  • It assists in choosing appropriate conditioning levels to avoid too many or too few pinhole occurrences, ensuring meaningful evaluation.

• Sample Preparation and Apparatus

  • Specifies specimen size, orientation, and mounting techniques to ensure repeatable results across tests.
  • Standardizes equipment setup, including mandrel spacing and movement, to replicate typical mechanical flexing conditions.

• Reporting Requirement

  • Outlines detailed reporting of applied flex conditions, test methods used post-conditioning, relevant data, and observations for comprehensive traceability.

Applications

• Flexible Packaging Assessment

  • Used extensively by manufacturers of flexible packaging materials for food, pharmaceuticals, and medical products to ensure product integrity under flex stresses encountered during distribution and use.

• Product Development and Quality Assurance

  • Enables R&D teams to benchmark new material formulations or structures for flex resistance.
  • Applied during routine quality control to verify product consistency and compliance with industry requirements.

• Regulatory Compliance

  • Supports compliance with international market access requirements where demonstration of flex durability and barrier performance is critical.

• Supplemental Testing

  • Often used in tandem with permeation tests, such as ASTM F1249 for water vapor transmission, and following guidelines from ASTM E171 and ASTM F2097 for environmental and design assessments.

Related Standards

• ASTM E171

  • Practice for Conditioning and Testing Flexible Barrier Packaging

• ASTM F1249

  • Test Method for Water Vapor Transmission Rate Through Plastic Film and Sheeting

• ASTM F2097

  • Guide for Design and Evaluation of Primary Flexible Packaging for Medical Products

Practical Value

Implementing ASTM F392/F392M-23 ensures robust material selection and process control during the development and production of flexible barrier materials. By standardizing conditioning procedures, companies can consistently evaluate how packaging materials perform under simulated mechanical abuse. This not only enhances product protection but also supports positive brand reputation, regulatory compliance, and customer satisfaction through reliable package performance in real-world conditions.

Keywords: flexible barrier materials, flex durability, pinhole resistance, packaging material conditioning, ASTM F392, gas permeation, water vapor transmission rate, packaging integrity, flex testing, packaging standards

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: F392/F392M − 23
Standard Practice for
Conditioning Flexible Barrier Materials for Flex Durability
This standard is issued under the fixed designation F392/F392M; the number immediately following the designation indicates the year
of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.
A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* 3. Terminology
1.1 This practice covers conditioning of flexible barrier 3.1 pinhole, n—a small opening of non-specific shape or
materials for the determination of flex resistance. Subsequent
dimension that passes completely through all layers of a
testing can be performed to determine the effects of flexing on
flexible material.
material properties. These tests are beyond the scope of this
3.1.1 Discussion—The use of the term “pin” provides the
practice.
relative size reference as in a small hole made with or as if with
a pin.
1.2 The values stated in either SI units or inch-pound units
are to be regarded separately as standard. The values stated in
4. Summary of Practice
each system may not be exact equivalents; therefore, each
system shall be used independently of the other. Combining
4.1 Specimens of flexible materials are flexed at standard
values from the two systems may result in non-conformance
atmospheric conditions defined in Practice E171, unless other-
with the standard.
wise specified. Flexing conditions, number of cycles, and
1.3 This standard does not purport to address all of the
severity of flexing strokes vary with the type of material
safety concerns, if any, associated with its use. It is the
structure being tested. Except for condition E, the flexing
responsibility of the user of this standard to establish appro-
condition consists of a twisting motion followed, in conditions
priate safety, health, and environmental practices and deter-
A to D, by a horizontal motion, thus, repeatedly twisting and
mine the applicability of regulatory limitations prior to use.
crushing the film. The frequency is at a rate of 45 cycles per
1.4 This international standard was developed in accor-
minute (cpm).
dance with internationally recognized principles on standard-
4.2 The effect of flexing on a material is determined by
ization established in the Decision on Principles for the
measuring the effect of the flex conditioning on the barrier
Development of International Standards, Guides and Recom-
and/or mechanical performance of the structure. The property
mendations issued by the World Trade Organization Technical
to be evaluated determines the appropriate conditioning level.
Barriers to Trade (TBT) Committee.
4.3 The various flex conditioning levels are summarized as
2. Referenced Documents
follows:
2.1 ASTM Standards: 4.3.1 Condition A—Full flex for 1 h (that is, 2700 cycles).
E171 Practice for Conditioning and Testing Flexible Barrier
4.3.2 Condition B—Full flex for 20 min (that is, 900 cycles).
Packaging
4.3.3 Condition C—Full flex for 6 min (that is, 270 cycles).
F1249 Test Method for Water Vapor Transmission Rate
4.3.4 Condition D—Full flex for 20 cycles.
Through Plastic Film and Sheeting Using a Modulated
4.3.5 Condition E—Partial flex for 20 cycles.
Infrared Sensor
F2097 Guide for Design and Evaluation of Primary Flexible
5. Significance and Use
Packaging for Medical Products
5.1 This practice is valuable in determining the resistance of
flexible packaging materials to flex-formed pinholes. Condi-
This practice is under the jurisdiction of ASTM Committee F02 on Primary
tioning levels A, B, or C are typically used. Reference Practice
Barrier Packaging and is the direct responsibility of Subcommittee F02.50 on
E171 and Guide F2097.
Package Design and Development.
Current edition approved Oct. 1, 2023. Published November 2023. Originally
5.2 Conditions D and E are typically used for determining
approved in 1974. Last previous edition approved in 2021 as F392/F392M – 21.
the effect of flexing on barrier properties and transmission rates
DOI: 10.1520F0392_F0392M-23.
related to gas and/or moisture.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
5.3 This practice does not measure or condition materials
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. for abrasion related to flex failure.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F392/F392M − 23
5.4 Failures in the integrity of one or more of the plies of a motion of 440° 6 4° in the first 90 mm [3.5 in.] of the stroke
multi-ply structure may require alternative testing. Supplemen- of the movable mandrel, followed by a straight horizontal
tary permeation testing using gas or water vapor can be used in motion of 65 mm [2.5 in.], so that at the closed position the
conjunction with the flex conditioning to measure the loss of mandrels are 25 mm 6 1 mm [1 in.] apart. The motion of the
ply integrity. Other test methods may be used after flexing for movable mandrel is reciprocal with a full cycle consisting of
assessment of presence of pinholes. For a list of test methods, the forward and return strokes.
refer to Guide F2097. 6.1.1 Fig. 1 shows the planar evolution of the helical groove
5.4.1 The various conditions described in this practice are to in the driven shaft to administer the required 440° (37° helix
prevent evaluating a material structure with an outcome of too angle) twisting motion and the straight horizontal motion.
many holes to effectively count (normally greater than 50), or 6.1.2 For the partial flex, Condition E, the movable head is
too few to be significant (normally less than five per sample). set to travel only 80 mm [3.25 in.] of the 180 mm [7 in.]
Material structure, testing basis, and a mutual agreement with spacing. Only approximately 90 % of the twisting stroke is
specified objectives are to be considered in the selection of utilized resulting in a twisting motion of 400°.
conditioning level for testing.
6.2 Tape, flexible, double-sided, pressure-sensitive, not
more than 13 mm [0.5 in.] wide.
6. Apparatus
6.3 Template, for cutting 200 mm by 280 mm 6 2 mm [8 in.
6.1 Flex Tester, is designed in accordance with Section 9.
by 11 in.] samples.
This apparatus shall consist essentially of a 90 mm 6 1 mm
[3.5 in.] diameter stationary mandrel and a 90 mm 6 1 mm
7. Test Specimens—All Conditions
[3.5 in.] diameter movable mandrel spaced at a distance of
7.1 Cut the samples into 200 mm by 280 mm [8 in. by
180 mm 6 2 mm [7 in.] apart from face-to-face at the starting
11 in.] flat sheets with the 200 mm [8 in.] dimension in the
position (that is, maximum distance) of the stroke. Mandrels
machine or transverse/cross direction. This will also be the
shall contain vents to prevent pressurization of samples. The
direction of the flex-tester motion axis.
specimen supporting shoulders on the mandrels shall be 13 mm
6 1 mm [0.5 in.] wide. The motion of the movable mandrel is
7.2 Flex condition specimen
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: F392/F392M − 21 F392/F392M − 23
Standard Practice for
Conditioning Flexible Barrier Materials for Flex Durability
This standard is issued under the fixed designation F392/F392M; the number immediately following the designation indicates the year
of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.
A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope Scope*
1.1 This practice covers conditioning of flexible barrier materials for the determination of flex resistance. Subsequent testing can
be performed to determine the effects of flexing on material properties. These tests are beyond the scope of this practice.
1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each
system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the
two systems may result in non-conformance with the standard.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
E171 Practice for Conditioning and Testing Flexible Barrier Packaging
F1249 Test Method for Water Vapor Transmission Rate Through Plastic Film and Sheeting Using a Modulated Infrared Sensor
F2097 Guide for Design and Evaluation of Primary Flexible Packaging for Medical Products
3. Terminology
3.1 pinhole, n—a small opening of non-specific shape or dimension that passes completely through all layers of a flexible material.
3.1.1 Discussion—
The use of the term “pin” provides the relative size reference as in a small hole made with or as if with a pin.
4. Summary of Practice
4.1 Specimens of flexible materials are flexed at standard atmospheric conditions defined in Practice E171, unless otherwise
specified. Flexing conditions, number of cycles, and severity of flexing strokes vary with the type of material structure being tested.
This practice is under the jurisdiction of ASTM Committee F02 on Primary Barrier Packaging and is the direct responsibility of Subcommittee F02.50 on Package Design
and Development.
Current edition approved May 1, 2021Oct. 1, 2023. Published April 2022November 2023. Originally approved in 1974. Last previous edition approved in 20152021 as
F392/F392M – 11 (2015).F392/F392M – 21. DOI: 10.1520F0392_F0392M-21.10.1520F0392_F0392M-23.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F392/F392M − 23
Except for condition E, the flexing condition consists of a twisting motion followed, in conditions A to D, by a horizontal motion,
thus, repeatedly twisting and crushing the film. The frequency is at a rate of 45 cycles per minute (cpm).
4.2 Flex failure The effect of flexing on a material is determined by measuring the effect of the tested flex conditioning on the
barrier and/or mechanical performance of the structure. The property to be evaluated determines the appropriate conditioning level.
4.3 The various flex conditioning levels are summarized as follows:
4.3.1 Condition A—Full flex for 1 h (that is, 2700 cycles).
4.3.2 Condition B—Full flex for 20 min (that is, 900 cycles).
4.3.3 Condition C—Full flex for 6 min (that is, 270 cycles).
4.3.4 Condition D—Full flex for 20 cycles.
4.3.5 Condition E—Partial flex for 20 cycles.
5. Significance and Use
5.1 This practice is valuable in determining the resistance of flexible packaging materials to flex-formed pinhole failures. pinholes.
Conditioning levels A, B, or C are typically used. Reference Practice E171 and Guide F2097.
5.2 ConditioningConditions D and E are typically used for determining the effect of flexing on barrier properties and transmission
rates related to gas and/or moisture.
5.3 This practice does not measure or condition materials for abrasion related to flex failure.
5.4 Failures in the integrity of one or more of the plies of a multi-ply structure may require alternative testing. Supplementary
permeation testing using gas or water vapor can be used in conjunction with the flex testconditioning to measure the loss of ply
integrity. Other test methods may be used after flexing for assessment of presence of pinholes. For a list of test methods, refer to
Guide F2097.
5.4.1 The various conditions described in this practice are to prevent evaluating a material structure with an outcome of too many
holes to effectively count (normally greater than 50), or too few to be significant (normally less than five per sample). Material
structure, testing basis, and a mutual agreement with specified objectives are to be considered in the selection of conditioning level
for testing.
6. Apparatus
6.1 Flex Tester, is designed in accordance with Section 9. This apparatus shall consist essentially of a 90 6 1-mm [3.5-in.]90 mm
6 1 mm [3.5 in.] diameter stationary mandrel and a 90 6 1-mm [3.5-in.]90 mm 6 1 mm [3.5 in.] diameter movable mandrel
spaced at a distance of 180 6 2 mm [7 in.] 180 mm 6 2 mm [7 in.] apart from face-to-face at the starting position (that is,
maximum distance) of the stroke. Mandrels shall contain vents to prevent pressurization of samples. The specimen supporting
shoulders on the mandrels shall be 13 6 1 mm [0.5 in.] 13 mm 6 1 mm [0.5 in.] wide. The motion of the movable mandrel is
controlled by an attached grooved shaft. For the full or maximum stroke, the groove is designed to give a twisting motion of
440440° 6 4° in the first 90 mm [3.5 in.] of the stroke of the movable mandrel, followed by a straight horizontal motion of 65
mm [2.5 in.], so that at the closed position the mandrels are 25 6 1 mm [1 in.] 25 mm 6 1 mm [1 in.] apart. The motion of the
movable mandrel is reciprocal with a full cycle consisting of the forward and return strokes.
6.1.1 Fig. 1 shows the planar evolution of the helical groove in the driven shaft to administer the required 440° (37° helix angle)
twisting motion and the straight horizontal motion.
6.1.2 For the partial flex, Condition E, the movable head is set to travel only 80 mm [3.25 in.] of the 180-mm [7-in.]180 mm [7 in.]
spacing. Only approximately 90 % of the twisting stroke is utilized resulting in a twisting motion of 400°.
6.2 Tape, flexible, double-sided, pressure-sensitive, not more than 13 mm [0.5 in.] wide.
F392/F392M − 23
FIG. 1 Planar Evolution of Gelbo Shaft Helical Groove 30.70-mm [1.20-in.]30.70 mm [1.20 in.] Diameter Shaft
6.3 Template, for cutting 200 mm by 280 mm 6 2-mm [8 by 11-in.]2 mm [8 in. by 11 in.] samples.
7. Test Specimens—All Conditions
7.1 Cut the
...